The empirical formula of an acid is $CH_2O_2$. The probable molecular formula of the acid may be:

In which of the following pairs is the percentage of carbon the same?

$A$ welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives $3.38 \, g$ of carbon dioxide,$0.690 \, g$ of water,and no other products. $A$ volume of $10.0 \, L$ (measured at $STP$) of this welding gas is found to weigh $11.6 \, g$. Calculate:
$(i)$ empirical formula,
$(ii)$ molar mass of the gas,and
$(iii)$ molecular formula.

In $CH_3CH_2Br$,the percentage of $Br$ is:

Analysis of a $60 \, g$ compound gives $C = 24 \, g$,$H = 4 \, g$,and $O = 32 \, g$. What is its empirical formula?

Which one has the highest percentage of nitrogen?